In the general field of liquid crystal displays and particularly in the field of active matrix liquid crystal displays, major international electronics companies have, for the last decade, expended hundreds of millions of dollars for the development of "large area" high resolution displays. To date, these efforts have resulted in the development of high resolution displays in sizes approximating that of relatively small television sets. To attain high resolution in even two, three, or five inch diagonal liquid crystal television displays, the aforementioned electronics manufacturers have used thin film amorphous silicon transistors and diodes to function as the switching elements by which the discrete liquid crystal pixels in the display could be addressed. As the size of the display increases, the number of rows and columns of pixels correspondingly increases in order to maintain the requisite resolution. However, as the number of rows and columns of pixels increases, it became increasingly difficult to address each pixel at video speed rates.
To date, several individuals have attempted to solve the problem of making large scale, full color, video speed display devices. None appear to have succeeded. For example, U.S. Pat. No. 4,559,480 to Nobs for "COLOR MATRIX DISPLAY WITH DISCHARGE TUBE LIGHT EMITTING ELEMENTS" describes a matrix board display comprising a plurality of rows and columns of light emitting elements. Each light emitting element is a florescent light tube. This type of display would be effective for manufacturing, for example, sign boards. However, the invention described in the '480 patent is incapable of displaying information at anything approaching video speed rate. The inherent on-off time of florescent tubes is far below that necessary to drive a pixel at 60 cycles per second. In addition, the light elements disclosed by Nobs are considerably larger and thicker, and hence heavier than the elements used in the instant invention. Moreover, the discharge tube lights disclosed in the Nobs patent are also known to be relatively energy inefficient, to generate considerable amounts of heat, and not readable in direct sunlight. U.S. Pat. No. 4,635,150 to Favreau for "LARGE SCREEN VIDEO DISPLAY COMPRISING A MATRIX ARRAY OF CATHODE RAY TUBES OPERATED AT INCREASED VERTICAL AND HORIZONTAL SCAN RATES" discloses a device comprising a plurality of rows and columns of cathode ray tubes for displaying a large area image. The invention of Favreau recognizes the problems inherent in abutting a large number of display elements: namely, the appearance of a seam at the area of the adjacent displays. Favreau attempts to resolve this problem by using either a Fresnel lens or a fiberoptic face plate over each cathode ray tube in order to distort the image projected by that tube. In this way, Favreau tries to "hide" the seams around each display.
The problems inherent in the approach described in Favreau include the use of cathode ray tubes which are known to be exceedingly large, heavy, and great consumers of energy. Moreover, the face plate approach employed by Favreau is not completely successful in eliminating the presence of the seams around each CRT.
U.S. Pat. No. 4,791,417 to Bobak for "DISPLAY DEVICE" discloses the use of a plurality of nematic or smectic liquid crystal cells for producing a large size, two dimensional display panel capable of half-tone operation. While Bobak discloses the concept of a large scale liquid crystal display panel, there are a number inherent limitations in the approach described therein. For example, Bobak describes a reflective display. There is no back light. Therefore, viewing the image displayed thereon is dependent upon reflected ambient light. Obviously, such a display cannot be used in the dark. Further, the display elements employed by Bobak are incapable of displaying information at video rates of operation. This is because Bobak's display elements are not "active matrix" type liquid crystal displays. Since Bobak's device is not "active matrix" it has poor contrast ratio and a limited viewing angle. This type of display is also unable to operate at elevated temperatures. Moreover, Bobak does not recognize the presence of optical seams around each display. Accordingly, Bobak does not make accommodation for eliminating such seams.